In recent years, there has been a demand for saws capable of cutting lumber from felled logs. Such saws are in demand because they eliminate the need to transport logs from the forest and to a saw mill, resulting in a savings of fuel and labor. Moreover, such portable saws enable lumber to be produced in remote locations where it is intended to be used.
So-called Alaska mills have been on the market. Such mills normally include attachments for standard chain saws to enable chain saws to cut boards from felled logs. Since saw chains are designed to cut transverse to the grain and not longitudinally thereof, such mills have not been as efficient as desired. Moreover, it has been difficult for even trained operators to cut straight boards efficiently with known Alaska mills. Also, so-called Alaska ladders must be nailed to the logs before the first cut is made in order to assure that a straight cut is made. This step is time consuming and requires materials not always readily available in remote forest locations. Furthermore, such mills tend to amplify undulations in successive cuts, and when cutting long boards, it is often necessary to drive wedges into the cut to prevent the board from pinching the saw blade. Also, a substantial amount of lumber is wasted because of the relatively wide kerf of a saw chain.
Various types of portable band saws are known for cutting lumber from felled logs. Examples of such saws may be found in the following U.S. Pat. Nos.: 3,530,908; 3,721,146; and 2,722,953. A hand-held band saw for splitting animal carcasses is disclosed in U.S. Pat. No. 4,160,320. One of the patented Alaska saw mills discussed above is disclosed in U.S. Pat. No. 3,225,799. Various types of commercially available saw mills are disclosed in the June 1978 issue of Popular Science magazine beginning at page 86.